So the seventh year of the Barack Obama administration, the first year of the new Republican Congress and the year before the 2016 presidential election now begins.

Like most years, it begins with much promise. Like most years, it holds great peril. But 2015 brings with it an unusual number of unanswered questions — questions that will shape the year and decade ahead. By this time next year, the answers to many of these questions should be apparent:

• How will the Republicans on Capitol Hill govern? With sturdy majorities in both chambers (but not large enough to override an Obama veto) the GOP is instantly transformed from a force to stop legislation into a force that must produce it.

It also is no longer in a position to claim credit for blocking appropriations bills, because those bills will come out of committees where the Republicans have majorities. And the budget resolution? That will be a compromise between the House and Senate budget committees, both controlled by Republicans. Budget resolutions are not subject to presidential vetoes. The GOP will have to produce a budget.

• Will Mr. Obama find accommodation with the Republican Congress? In the weeks following his party’s midterm election debacle, Mr. Obama has taken two parallel paths: He has talked of conciliation. And he has looked for opportunities, most particularly in immigration, where he believes he can act without congressional approval.

But by doing the latter, he has undermined his efforts at the former, and the tension between the two tactics will not endure into the new year. The president cannot ignore Congress forever. He wants the Senate to confirm Loretta Lynch as attorney general. And if Ruth Bader Ginsburg or another associate justice retires, he will want his Supreme Court nominee confirmed.

That is a more subtle matter than it may appear. Civil relations with the new GOP Senate would give him far more latitude in selecting a Supreme Court nominee than if there is unremitting tension between the White House and Capitol Hill.

• How will the insurgents in the Republican presidential race differentiate themselves from each other? Right now these GOP rebels are often lumped together, as if there were a mighty, but untested, force in Republican politics known as Sen. Paul Cruz Rubio. There are actually three senators with that profile, Rand Paul of Kentucky, Ted Cruz of Texas and Marco Rubio of Florida.

One, two or all three might run for president, along with some other insurgents, such as Govs. Mike Pence of Indiana and Scott Walker of Wisconsin. They speak to broadly the same audience, their distinctions (right now) known only to the most avid readers of the conservative press and websites.

The process of differentiation has begun, tentatively. An important break in the insurgent ranks last year: Mr. Paul supported Mr. Obama’s Cuba initiative, which is ardently opposed by Mr. Rubio, who is the son of Cuban immigrants, and by Mr. Cruz, whose Cuban father once supported Fidel Castro but later became a Castro opponent.

• Will the Republican establishment rally behind one candidate? That is the Republican establishment’s fondest hope, though its members cannot now agree on which establishment figure it should be. Besides former Gov. Jeb Bush of Florida, possible White House candidates include Gov. Chris Christie of New Jersey and former Gov. Mitt Romney of Massachusetts. Mr. Romney has run twice, been nominated once and is being urged by supporters to run or withdraw swiftly, permitting his 2008 and 2012 organizers and funders to drift into other camps, principally the emerging Bush campaign.

Though the Republican rebels like to portray the GOP establishment as a stubborn conspiracy rooted in 1960s-era Eastern power centers, the members of this group are no more monolithic than are their opponents further to the right on the political spectrum. Some top Romney supporters are cool to Mr. Bush, while some will drift into the Bush camp.

• Will Hillary Rodham Clinton face a strong competitor for the 2016 Democratic presidential nomination? Political professionals like to say that presidential nominees are strengthened by defeating other party members in the primaries, but they ordinarily say that only when their plans of floating to the nomination are disrupted by an irritating challenger.

Still, there is truth to that old chestnut. Ronald Reagan was a stronger candidate in 1980 for having defeated George H.W. Bush, and the elder Bush was a stronger candidate eight years later for having defeated Sen. Robert J. Dole of Kansas, Rep. Jack F. Kemp of New York and the Rev. Pat Robertson of Virginia. Similarly, Gov. Bill Clinton was a stronger candidate in 1992 for having defeated Sen. Robert J. Kerrey of Nebraska and former Sen. Paul E. Tsongas of Massachusetts.

The political world abhors a vacuum, and Mrs. Clinton will have an opponent, or a few of them, even if her campaign is built on the notion of inevitability. Someone is going to win the crown as “the anti-Hillary,” and right now Gov. Martin O’Malley, who retains his office in Maryland for another week, and former Sen. James Webb of Virginia are contending for the title.

Mr. O’Malley will assail Mrs. Clinton from the left, Mr. Webb from the right. Today neither is well-known, though both have powerful personalities and sharp intelligence. Mr. O’Malley dates his political involvement to the 1984 Gary Hart campaign during his college days and has had a steady rise in Baltimore and Maryland politics. Mr. Webb is a Vietnam veteran, a celebrated novelist, a Reagan appointee as Secretary of the Navy and a senator. Neither registers much in the polls, but either could be a formidable opponent to Mrs. Clinton in a primary debate.

• Is the 2016 election shaping up as an extension of the 2012 presidential election or of the 2014 midterm election? Only the contours of the answer will be apparent by this time next year, but the resolution of this question has massive consequences. It will depend on which elements of the public are motivated, which issues are prominent and which candidates emerge. And it will determine who occupies the White House two years from now.

David Shribman, a Pulitzer Prize winner in journalism, is executive editor of the Pittsburgh Post-Gazette.